Organic light emitting display

Abstract

Disclosed is an organic light emitting display having a mirror function. In an embodiment, a light-shielding reflective layer overlaps areas of the organic light emitting display except for emission areas provided with light emitting devices formed therein. The light-shielding reflective layer prevents light from entering channel regions of active layers and reflects external light, for example, when the organic light emitting device is not operated to display an image, and thus the organic light emitting display may stably implement a mirror function.

What is claimed is: 
     
       1. An organic light emitting display comprising:
 a light emitting device disposed in an emission area of a substrate, the light emitting device emitting internal light through the emission area of the substrate; 
 a light-shielding reflective layer on the substrate overlapping a non-emission area of the substrate to reflect external light incident through the substrate; 
 a plurality of thin film transistors on the substrate, the plurality of thin film transistors overlapping the light-shielding reflective layer, wherein the light-shielding reflective layer overlaps an area between the plurality of thin film transistors; and 
 a plurality of pads on the substrate, wherein the light-shielding reflective layer overlaps the plurality of pads and an area between the plurality of pads. 
 
     
     
       2. The organic light emitting display according to  claim 1 , further comprising a buffer film on the substrate and the light-shielding reflective layer to cover the light-shielding reflective layer. 
     
     
       3. The organic light emitting display according to  claim 2 , further comprising a pixel circuit configured to drive the light emitting device,
 wherein the pixel circuit includes: 
 the plurality of thin film transistors including a driving thin film transistor connected between the light emitting device and a high voltage supply line and a switching thin film transistor connected between the driving thin film transistor and a data line; and 
 a storage capacitor connected to the driving thin film transistor and the switching thin film transistor, 
 wherein active layers of the driving thin film transistor and the switching thin film transistor overlap the light-shielding reflective layer, the buffer film interposed between the active layers and the light-shielding reflective layer. 
 
     
     
       4. The organic light emitting display according to  claim 3 , further comprising:
 a scan line connected to a gate electrode of the switching thin film transistor; 
 a data line connected to a first source electrode of the switching thin film transistor;
 the high voltage supply line connected to a second source electrode of the driving thin film transistor; and 
 a low voltage supply line connected to a cathode of the light emitting device, 
 wherein the light-shielding reflective layer overlaps at least one of the scan line, the data line, the high voltage supply line, and the low voltage supply line. 
 
 
     
     
       5. The organic light emitting display according to  claim 4 , further comprising the plurality of pads configured to supply a driving signal to the scan line, the data line, the high voltage supply line, and the low voltage supply line,
 wherein the light-shielding reflective layer overlaps all pad area of the substrate provided with the plurality of pads. 
 
     
     
       6. The organic light emitting display according to  claim 3 , wherein the storage capacitor includes:
 a storage lower electrode connected to the switching thin film transistor; and 
 a storage upper electrode connected to the driving thin film transistor, 
 wherein the storage lower electrode and the storage upper electrode are composed of transparent material and are disposed in the emission area of the substrate. 
 
     
     
       7. The organic light emitting display according to  claim 6 , wherein the storage lower electrode is formed of a same material as the active layers, and
 wherein the storage upper electrode extends from a transparent conductive layer of a drain electrode of the driving thin film transistor. 
 
     
     
       8. The organic light emitting display according to  claim 1 , further comprising:
 a light-shielding pad connected to the light-shielding reflective layer; and 
 a flexible printed circuit board film having a signal supply terminal supplying a base voltage or a low voltage to the light-shielding reflective layer. 
 
     
     
       9. The organic light emitting display according to  claim 8 , wherein:
 the light-shielding pad extends from the light-shielding reflective layer and is exposed through a light-shielding contact hole passing through a plurality of insulating films disposed on the light-shielding reflective layer; and
 the light-shielding pad is connected to the flexible printed circuit board film. 
 
 
     
     
       10. The organic light emitting display according to  claim 8 , wherein the light-shielding pad includes:
 a light-shielding lower electrode extending from the light-shielding reflective layer; 
 a light-shielding contact hole passing through a plurality of insulating films disposed on the light-shielding lower electrode; and 
 a light-shielding upper electrode connected to the light-shielding lower electrode exposed through the light-shielding contact hole, 
 wherein the light-shielding upper electrode of the light-shielding pad is connected to the flexible printed circuit board film. 
 
     
     
       11. The organic light emitting display according to  claim 8 , further comprising:
 a conductive film connecting a signal supply terminal of a flexible printed circuit board film to the light-shielding pad. 
 
     
     
       12. The organic light emitting display according to  claim 8 , wherein the light shielding pad is formed of a same material as the light shielding reflective layer. 
     
     
       13. The organic light emitting display according to  claim 1 , wherein the light-shielding reflective layer has a single layer structure or a multilayer structure including material selected from a group consisting of Mo, Ti, Al, Cu, Cr, Co, W, Ta, Ni, MoTi, CuNx, and, Cr. 
     
     
       14. The organic light emitting display according to  claim 13 , wherein the light-shielding reflective layer has a multilayer structure,
 wherein the light-shielding reflective layer made of Ti has a first thickness of 500 Å to 1000 Å, 
 wherein the light-shielding reflective layer made of Mo has a second thickness of 300 Å to 700 Å, 
 wherein the light-shielding reflective layer made of Cu has a third thickness of 700 Å to 2000 Å, 
 wherein the light-shielding reflective layer made of MoTi has a fourth thickness of 300 Å to 500 Å, and 
 wherein the light-shielding reflective layer made of Al has a fifth thickness of 500 Å to 2000 Å. 
 
     
     
       15. The organic light emitting display according to  claim 1 , wherein:
 the external light incident through the substrate is reflected by the light-shielding reflective layer at the non-emission area of the substrate; and 
 the internal light is generated by the light emitting device and is reflected by a cathode of the light emitting device. 
 
     
     
       16. The organic light emitting display according to  claim 1 , further comprising a color filter between the substrate and a light emitting layer. 
     
     
       17. The organic light emitting display according to  claim 1 , wherein the non-emission area of the substrate is larger than the emission area of the substrate. 
     
     
       18. The organic light emitting display according to  claim 1 , wherein the non-emission area comprises areas other than emission areas of sub-pixels, a non-emission area of a sub-pixel being larger than an emission area of the sub-pixel. 
     
     
       19. The organic light emitting display according to  claim 1 , wherein the light-shielding reflective layer is disposed in all non-emission areas except for the emission area of the substrate. 
     
     
       20. An organic light emitting display comprising:
 a light emitting device configured to emit light through an emission area of a transparent substrate for displaying an image in a light emission mode; 
 a pixel driving circuit coupled to the light emitting device and configured to drive the light emitting device, wherein the pixel driving circuit comprises a plurality of thin film transistors; 
 a light-shielding reflective layer between the transparent substrate and the pixel driving circuit, the light-shielding reflective layer configured to reflect external light passing through the transparent substrate in a mirror mode, wherein the light-shielding reflective layer overlaps an area between the plurality of thin film transistors; and 
 a plurality of pads on the transparent substrate, wherein the light-shielding reflective layer overlaps the plurality of pads and an area between the plurality of pads. 
 
     
     
       21. The organic light emitting display of  claim 20 , wherein the light emitting device is turned off during the mirror mode. 
     
     
       22. The organic light emitting display according to  claim 20 , wherein the plurality of thin film transistors comprises:
 a driving thin film transistor having a terminal connected to the light emitting device to provide current to the light emitting device, and 
 a switching thin film transistor between a data line and the driving thin transistor to provide a data signal to the driving thin transistor, the light-shielding reflective layer spanning across the driving thin film transistor and the switching thin film transistor. 
 
     
     
       23. The organic light emitting display according to  claim 20 , further comprising:
 a buffer film between the light-shielding reflective layer and the pixel driving circuit; and 
 a pad on the buffer film and overlapping the light-shielding reflective layer, the pad including a first pad electrode and a second pad electrode over the first pad electrode. 
 
     
     
       24. The organic light emitting display according to  claim 23 , wherein the first pad electrode is formed of a same material as gate electrodes of thin film transistors in pixel driving circuit. 
     
     
       25. The organic light emitting display according to  claim 23 , wherein the second pad electrode is formed of a same material as source and drain electrodes of thin film transistors in pixel driving circuit. 
     
     
       26. The organic light emitting display according to  claim 23 , wherein the pad further comprises a pad cover electrode on the second pad electrode, the pad cover electrode formed of a same transparent material as an anode of the light emitting device. 
     
     
       27. The organic light emitting display according to  claim 23 , wherein the pad is electrically coupled to a cathode of the light emitting device to generate the light emitted by the light emitting device. 
     
     
       28. The organic light emitting display according to  claim 20 , wherein a non-emission area of the transparent substrate is larger than the emission area of the transparent substrate. 
     
     
       29. The organic light emitting display according to  claim 20 , wherein a non-emission area comprises areas other than emission areas of sub-pixels, a non-emission area of a sub-pixel being larger than an emission area of the sub-pixel. 
     
     
       30. The organic light emitting display according to  claim 20 , further comprising a color filter between the transparent substrate and a light emitting layer.